ruby_de_ruby_8_interp.rb

require "minruby"

def evaluate(tree, genv, lenv)
#  pp(tree)
  case tree[0]
  when "func_def"
    genv[tree[1]] = ["user_defind", tree[2], tree[3]]
  when "lit"
    tree[1]
  when "+"
    evaluate(tree[1], genv, lenv) + evaluate(tree[2], genv, lenv)
  when "-"
    evaluate(tree[1], genv, lenv) - evaluate(tree[2], genv, lenv)
  when "*"
    evaluate(tree[1], genv, lenv) * evaluate(tree[2], genv, lenv)
  when "/"
    evaluate(tree[1], genv, lenv) / evaluate(tree[2], genv, lenv)
  when "<"
    evaluate(tree[1], genv, lenv) < evaluate(tree[2], genv, lenv)
  when ">"
    evaluate(tree[1], genv, lenv) > evaluate(tree[2], genv, lenv)
  when "=="
    evaluate(tree[1], genv, lenv) == evaluate(tree[2], genv, lenv)
  when "func_call"
    args = []
    i = 0
    while tree[i+2]
      args[i] = evaluate(tree[i+2], genv, lenv)
      i = i + 1
    end
    mhd = genv[tree[1]]
    if mhd[0] == "builtin"
      minruby_call(mhd[1], args)
    else
      new_lenv = {}
      params = mhd[1]
      i = 0
      while params[i]
        new_lenv[params[i]] = args[i]
#        lenv[params[i]] = args[i]
        i = i + 1
      end
#      evaluate(mhd[2], genv, lenv)
      evaluate(mhd[2], genv, new_lenv)
    end
  when "stmts"
    i = 1
    last = nil
    while tree[i] != nil
      last = evaluate(tree[i], genv, lenv)
      i = i+1
    end
    last
  when "var_assign"
    lenv[tree[1]] = evaluate(tree[2], genv, lenv)
  when "var_ref"
    lenv[tree[1]]
  when "if"
    if evaluate(tree[1], genv, lenv)
      evaluate(tree[2], genv, lenv)
    else
      evaluate(tree[3], genv, lenv)
    end
  when "while"
    while evaluate(tree[1], genv, lenv)
      evaluate(tree[2], genv, lenv)
    end
  when "while2"
    evaluate(tree[2], genv, lenv)
    while evaluate(tree[1], genv, lenv)
      evaluate(tree[2], genv, lenv)
    end
  end
end

str = minruby_load()
tree = minruby_parse(str)

def add(x,y)
  x + y
end

genv = { "p" => ["builtin", "p"], "add" => ["builtin", "add"] }
lenv = {}
evaluate(tree, genv, lenv)

# $ ruby interp.rb program1.rb
# program1.rb
# def foo(x,y)
#   x + y
# end
#
# x = 1
#
# p(foo(2,4))
# p(x)